


Vice Versa

by centaury_squill



Category: Harry Potter - J. K. Rowling
Genre: M/M
Language: English
Status: Completed
Published: 2011-06-16
Updated: 2011-06-16
Packaged: 2017-10-20 11:36:37
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 6,926
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/212383
Author URL: https://archiveofourown.org/users/centaury_squill/pseuds/centaury_squill
Summary: <blockquote class="userstuff">
              <p>Snape is determined that Harry won't suffer as he did. But that's just the start.</p>
            </blockquote>





	Vice Versa

**Author's Note:**

> 1.Written for Snarry-a-thon 2011 Prompt #046: Slughorn has abused members of his slug club before (Snape specificially). "You said he'll try to collect me. Do you want me to let him?" Severus discovers that the headmaster is willing to use Harry as bait in order to find that memory and he is appalled at such a breach of trust. How does Snape prevent Slughorn from doing to Harry what he did to him all those years ago? Maybe he polyjuices into Harry and takes his place, or something else? You decide.
> 
> 2\. Any bits you recognise were shamelessly Accio'd from Harry Potter and the Half-Blood Prince.

Snape strides impatiently out into the snowy courtyard, sees Potter and Granger with their heads together, stops in his tracks. What are they plotting now? He ghosts towards them, keeping to the shadows, unobtrusive; catches the word _Dumbledore_ in Potter's excited tones. Aha! Maybe the brat is telling little Miss Know-it-all about his _private lessons_ with the Headmaster. These have niggled at Snape ever since Dumbledore persuaded him to postpone Potter's detention, but whenever he's asked what they're doing, closeted alone together in the Headmaster's office, Dumbledore has brushed him off with an airy _All in good time, Severus_. Now, perhaps, he'll learn the secret. He sidles closer.

"... showed me another memory. Slughorn's. Only he'd tampered with it."

"Slughorn tampered with his own memory? Why, Harry? Did Dumbledore say?"

"Reckoned old Sluggie was ashamed of it, trying to show himself in a better light. Tom Riddle was asking him about Horcruxes, and he'd bollixed the memory so it sounded like he gave him the brush-off. But Dumbledore doesn't think that's what really happened, and he wants me to get the real memory out of Sluggie."

"Horcruxes? _Horcruxes_... I've never heard of them."

"Gosh, Hermione, finally a gap in your knowledge..."

Snape smirks at this, but it's wiped off his face at Potter's next words.

"Dumbledore once told me that Slughorn would try to collect me. Looks like I'll have to let him."

Potter carries on talking, but Snape no longer hears him; he's back in the past.

Hogwarts, 1976, when he was sixteen, the age Potter is now, the age Slughorn likes them. That night in Slughorn's office, high on potions and teenage hormones. Writhing naked on the floor, his own wand up his arse, masturbating till he came, Slughorn watching greedily. Ending the evening with a mouthful of Sluggie's cock.

The utter disgust he felt the next day.

Snape clenches his fist. Dumbledore _knows_ about Slughorn's propensities, the hushed-up scandal which led to his retirement in the first place. How can he possibly justify encouraging Potter – who obviously has no idea what he's getting into – to throw himself in the path of this monster?

Granger's shrill tones break in on his thoughts.

"Oh well, if _Won-Won_ thinks it's a good idea –"

What's she talking about?

"I think I will, though, Hermione. I'll hang back after Potions this afternoon, get Sluggie on his own, see if I can have a private word..."

Snape has a sudden mental image of Potter on his knees in front of Slughorn, vivid green eyes blinking up at him helplessly. He shakes his head vehemently. Not going to happen. Not if he can prevent it – and he's sure he can.

*

  


Harry hurries down the steps towards the dungeons; he'll be late for Potions if he's not careful. He's spent too long poring over the Marauders Map, obsessing about what Malfoy's up to – and in the end the little wanker's heading for class after all. Still looking at the Map, where the pointy footprints labelled _Draco Malfoy_ are just entering the Potions classroom, Harry doesn't notice the door of Filch's store room is slightly ajar as he passes by. He pulls out his wand, taps the Map, but before he can say _Mischief Managed_ , the door opens fully, a strong hand seizes his collar, and he's dragged inside. The door slams behind him, and he finds himself blinking up at the loathed features of Severus Snape.

"What the fuck –"

"Manners, Potter," Snape says, giving a lazy flick with his wand.

Instantly, Harry freezes in position, arms and legs immobilised. He can still move his head, however. So not quite a full body-bind, then. Feeling a reluctant admiration for Snape's spellcraft, Harry follows his teacher's gaze down to the Map in his hand. Oh shit, no...

"What have we here, Mr Potter?" Snape asks, deftly plucking the parchment from Harry's nerveless fingers.

"Mischief Managed!" Harry shouts.

The Map ignores him.

"Well, well," Snape says softly, intently scanning the parchment. "How... _interesting_."

He looks up, black eyes fixed on Harry's. Harry struggles to empty his mind, knows it's useless. But after a moment Snape simply shrugs, puts the parchment down on a packing case and picks up a goblet of muddy liquid. Harry realises what it is even before Snape tweaks a hair from his, Harry's, head and drops it into the goblet. The Polyjuice Potion steams, bubbles, turns a bright gold shot through with angry red streaks. Snape looks faintly surprised, but swigs down the potion without comment.

Harry watches helplessly as Snape's features blur, melt, reform: a moment later his own face is glaring myopically back at him.

"God, Potter, your eyesight's crap," Snape grumbles. He's even got the voice right, though Harry thinks resentfully that he doesn't sound as much of a stroppy teenager as all _that_. Snape grabs Harry's glasses, jams them on his own nose. Now he's reduced to a blur.

"I'll have that, too," the blur says, tugging at Harry's wand. But Harry's fingers are firmly frozen around it. Snape casts a quick spell, Harry feels himself unfreeze, but before he can even think of reacting Snape has twitched the wand away.

"And I'll need your clothes."

Harry balls his fists, strikes out at the blurred outline of his look-alike, which easily evades him.

"You can take them off yourself, or I'll take them off for you." Snape's using his own voice this time: quiet, silky, laced with menace.

Convinced now that Snape must have gone mad, Harry decides he'd better humour him. He struggles out of his clothes until he's standing there in his boxers. His Gryffindor-red boxers, covered in a pattern of flying golden Snitches. He hears a snigger.

"Ginny gave them me for Christmas," he says defensively, and feels himself going as red as his underwear.

This time he hears a contemptuous snort.

"Why are you doing this?" Harry asks. The air feels chilly on his naked skin. He tries not to shiver, doesn't want Snape to think he's afraid.

Silence for a moment, then Snape says brusquely, "You'll thank me, one day."

The next minute, he's gone. Harry hears the door shut, the click of the key in the lock.

He's alone.

*

  


Snape affects a teenage swagger as he strolls into Slughorn's dungeon classroom. Worrying, how at home he feels in Potter's skin. He pauses by the door, scans the room. Draco Malfoy looks up from his cauldron and sneers at him. Snape's eye travels on. Ah, that must be his place, beside the Weasley boy. He drags a stool out from under the table, drops Potter's school bag onto the floor, sits down. Little Miss Know-it-all immediately moves her cauldron around the table and moves closer to the Hufflepuff boy, pointedly ignoring both himself and Weasley.

"What've _you_ done?" mutters Weasley.

But he's saved from replying – just as well, since he hasn't a clue what Potter has done to annoy her – by Slughorn calling for silence.

"Settle down, please! Quickly now, lots of work to get through this afternoon! Golpalott's Third Law... who can tell me –? But Miss Granger can, of course!"

Oh, _of course_. The annoying little Mudblood shows off as usual, parroting Golpalott's Third Law word for word from the textbook. He glances covertly around the table. Just as well she's apparently not speaking to Potter at the moment; he's sure she'd be onto any slips he might make. Weasley, on the other hand, won't notice a thing – look at the idiot now, mouth open, practically drooling.

They all fetch phials of potion from Slughorn's desk. He's just wondering exactly how to screw up – of course _he_ knows how to create an antidote to the poison in the phial, but Potter wouldn't have a clue – when Granger addresses him.

"It's a shame that the Prince won't be able to help you with this, Harry," she says brightly. "You have to understand the principles involved this time. No short cuts or cheats!"

 _The Prince? Short cuts? Cheats?_ A suspicion first formed when Slughorn sang Potter's praises at his Christmas party comes back to mind. It's confirmed when Weasley mutters to him, "You sure the Prince hasn't got any tips?" And nods towards his own textbook.

Fuming, Snape pulls _Advanced Potion-Making_ out of Potter's bag, flips it open. Just as he thought. So that's where the bloody thing went. Slughorn must've stolen it – a memento? Sick bastard. And now the Potter brat is using his – _his!_ annotations to masquerade as a genuine potioneer. He forces himself to be calm, to remember his own masquerade.

"Nothing," he mutters back at Weasley, leafing through the chapter on Antidotes. He remembers doing Golpalott in his own sixth year, thinking what a waste of time and effort it was, really, considering you could... ah, yes, there it is, scrawled in his own handwriting...

 _Just shove a bezoar down their throats._

A smirk spreads across his face. He jumps up, hurries to the store cupboard, rummages around until he finds a small cardboard box labelled _Bezoars_.

He's back in his place, the little wizened object clutched in his fist, by the time Slughorn starts his rounds. When he reaches their table he asks, "And you, Harry. What have you got to show me?"

Snape bares his teeth in a stupid grin and holds out his open hand, the bezoar sitting on his palm. If this doesn't get points taken off Gryffindor, nothing will.

But apparently he's underestimated Slughorn's infatuation with The Chosen One. The fat fool stands gawping down at the bezoar for a good ten seconds, then throws his head back and roars with laughter.

"You've got a nerve, boy! Oh, you're like your mother... well, I can't fault you... a bezoar would certainly act as an antidote to all those poisons!"

Granger is looking furious. "And you thought of a bezoar all by yourself, did you, Harry?" she hisses.

He knows how she feels.

The travesty of a lesson finally comes to an end. Far from deducting points, Slughorn actually awards an extra ten to Gryffindor – _for sheer cheek._ Snape clenches his fists, has to remind himself who he's supposed to be, and what he's here for. He hangs back until he and Slughorn are the only two left in the room.

"Come on, now, Harry, you'll be late for your next lesson," Slughorn says.

"This won't take long," he murmurs seductively. He moves closer, knowing exactly how to push Slughorn's buttons, wishing he didn't.

Slughorn's fat fingers falter on his briefcase's gold catches. "Harry?" he says, pink tongue coming out to moisten his lips. "What are you doing?"

"Something I know you like," he says, sinking to his knees, his expression half knowing, half abashed. His hand strays downwards, strokes himself through his clothes. A part of his brain notes that Harry is surprisingly well-endowed for his age and size.

Slughorn makes a muffled little sound, casts a hasty glance around to make sure they're alone. He can't resist this tempting treat. Parting his robes, he frees his own erection, nudges it encouragingly against his pupil's lips. "Just a quickie, then, Harry," he whispers hoarsely.

Snape resists the temptation to bite him. Instead, he gets to his feet and says coldly, "If you ever touch me again, I'll go to my friend Rita Skeeter on the _Daily Prophet_. I'm sure she'd love to publish this story."

Slughorn hurriedly tucks himself away. "How dare you, boy," he blusters. "Your word against mine."

"I think people will believe _The Chosen One_ ," Snape says. He can't help sneering at Potter's title, but Slughorn misunderstands his emphasis and goes pale.

Snape picks up Potter's school bag, turns to leave. "Oh," he says idly, "I almost forgot. What do you know about... Horcruxes? I'm sure the _Daily Prophet_ would be interested in that story, too."

"Dumbledore's shown you that – that memory," Slughorn whispers. He sounds terrified. "Well? Hasn't he?"

"Oh, yes," Snape says airily, and smiles.

"Well, then you'll know I don't know anything about Horcruxes," Slughorn says. He picks up his dragonskin briefcase and marches towards the door. "I know nothing at all! NOTHING!" And he slams the dungeon door shut behind him.

Snape is left smirking to himself. This should keep the boy safe from Sluggie's clutches.

An idea occurs to him. Just to be absolutely sure... he opens the door. Slughorn is already halfway down the corridor. Snape casts a swift Disillusionment charm and speeds after him. He speaks in his own voice, low and menacing.

"Up to your old tricks, Horace?"

Slughorn spins, staring wildly all around. But the Disillusionment charm holds: all he sees are the shadowy stone walls of the corridor.

"S-Snape? Where are you?"

"I'm watching you, Horace. I'm always watching you. And if I _ever_ catch you alone with Potter again, dire consequences will follow. Do you understand?"

He watches in satisfaction as Slughorn nods frantically, wipes his podgy sweaty face, waddles off down the corridor. He's won; the boy should _definitely_ be safe now.

*

  


Harry's sitting on an upturned bucket, hunched up in Snape's discarded robes, reluctantly donned to keep himself warm. He'd like to kill Snape. If only he had his wand...

Suddenly there's the click of the lock and the door opens. Harry screws up his eyes and squints into the comparative brightness.

"Snape? Is that you? Give me back my stuff!"

"All in good time. We need to go to my rooms first."

Harry feels a tap, the sensation of an egg breaking on his head and dripping down: a Disillusionment charm. His hand's seized and he's pulled up off the bucket. Staggering, trying to keep his balance, he follows his persecutor out of the store cupboard, along the dungeon corridors and into Snape's rooms, where Snape removes the Disillusionment charm from them both. Harry blinks at him resentfully.

"What the fuck is all this?" he shouts.

"Calm down. I've just had to put up with Slughorn trying to fuck my face for you."

" _What?_ What the flying fuck have you been doing?"

Snape tells him.

Harry's appalled. How's he ever going to look Slughorn in the face again?

"Thanks a bunch," he snarls. "I don't have a chance in hell of getting that memory now. How did you know about it, anyway?"

"I'm sure there are other methods for getting this memory that Dumbledore wants so much. Ones that don't involve you being... abused."

Snape's tone is bitter. Harry wonders how he could be so sure that Slughorn would try and take advantage of him, then, suddenly, he knows.

"He did it to you, didn't he? When you were a kid, I mean."

Snape doesn't reply, but Harry is sure he's right. Merlin, that must have been... it was... he doesn't know what to say.

"Um. Thanks," he mumbles at last.

Snape makes an abrupt movement, as if fending something off. "Well. I suppose I'd better..." His voice dies away.

"What?" demands Harry.

There's a long pause.

Snape's voice is strained as he says, "We may have a slight problem..."

*

  


He can't believe this is happening. He invented it himself: an improvement on the old Polyjuice potion, which always suffered from the drawback of wearing off after one hour. His version lasts as long as the user wants it to – at least, that's the theory. He's sure he doesn't want to stay looking like Harry Potter a moment longer than he has to. And yet, here he still is: untidy hair, lightning bolt scar, bad eyesight, and all. He scowls at himself in the mirror, concentrating on the non-verbal spell which is supposed to return him to normality.

Still nothing. And he's supposed to be teaching a class about half an hour from now. There's only one thing for it.

"You'll have to Polyjuice into me," he informs Potter.

" _What?_ " yelps the brat. "Why?"

Reluctantly, he explains.

"Not such a brilliant potion inventor as all that, then!" Damn the boy, he's _grinning_. "...Anyway, why not just Polyjuice into yourself? Simple!"

Snape shakes his head. Impossible to predict the effect of the two potions on top of one another; he'd probably end up as some horrendous mixture of himself and Potter, like their bastard love-child. Vindictively, he shares this thought. Heh. That wiped the smile off the brat's face.

"Okay, then..." Potter says slowly. "But I'm buggered if I'm taking your... _improved_ " – he makes sarcastic quotation marks with his fingers – "version. It's the original Polyjuice for me. If you've got any."

Snape huffs. "Yes, I have. But you'll have to remember to take it every hour, or else –"

"Yeah, whatever," the brat interrupts. "Gimme a hip flask full of the stuff, then."

Snape finds one of his own long black hairs caught in a comb, unlocks his store cupboard, mixes the required potion in a flask, hands it to Potter.

The brat looks thoughtful. "I don't really fancy being you, but it'll be fun to teach Defence Against the Dark Arts."

Snape pales. "Just keep them reading the textbook. Or, perhaps you should report sick... keep to these rooms until I can solve the problem..."

"No way," Potter says cheerfully, glugging down a mouthful of the potion. "DADA – here I come!"

*

Harry's halfway to the DADA classroom before he realises he doesn't know which class he's supposed to be taking when. Oh well, better make a quick detour into the staffroom, where he knows there's a complete curriculum Spell-o-taped to the wall. He hopes that Snape's had the sense to look in his book bag for Harry's timetable and get himself to Harry's next lesson. Merlin, this is so weird...

He pauses at the staffroom door to compose his features into a suitably Snape-like sneer before sweeping in with a swirl of robes. His acting skills are wasted, however; he's the only person there apart from Filch, who's fussing about with a giant tea urn.

A quick glance at the wall tells him Snape has just one more lesson scheduled for this afternoon, with third year Hufflepuffs and Ravenclaws, due to begin – he looks up at the big, ornately decorated clock – in about twenty minutes.

"Nice cup of tea, Professor?"

He turns. Filch is leering at him ingratiatingly. Unsure of Snape's tea-drinking preferences, he plays safe and shakes his head.

"You're looking a bit frazzled, Professor, if you don't mind my saying. Little bastards playing up again, are they?" Filch sucks his teeth. "Dear, dear. How about popping along to my room for a spot of the usual, soon perk you up, that will."

The usual? What the hell's that? Harry hesitates, torn between curiosity and caution. Curiosity wins; he gives a curt nod, hoping _the usual_ will turn out to be Firewhisky – he could certainly do with some – and follows Filch to the caretaker's lair, where he's solicitously established in a comfortable armchair and handed a brimming glass.

It becomes apparent there's more than Firewhisky on offer when Filch gets creakily down on his knees and reaches for what he thinks is Snape's crotch.

Harry's first, panicked, reaction is to go for his wand – before realising that Snape has still got both of them. Helpless, he leans back in the chair and allows Filch to part his robes.

Filch murmurs encouragement. "That's it, Professor, you let old Argus take care of you... mmm... that's it... oh, yes..."

Harry desperately gulps Firewhisky.

"Ooh, Professor, you're so tense... those little bastards must've been givin' you a hard time... relax, now... yes, that's better..."

Harry, confused to find he's enjoying Filch's ministrations, tells himself his Polyjuiced body must simply be mimicking Snape's reactions. And who'd have thought Snape and Filch had a thing going on...?

"Ah, yes, that's it... what a lovely cock you've got, Professor, let old Argus look at you..."

Turning slightly to put his empty glass down, Harry catches sight of himself in the caretaker's full-length mirror. He certainly never expected to see such a look of utter bliss on Snape's features. But he's shocked to discover that he's aroused most by the appearance of Snape's massive hard-on.

Now he's _really_ confused.

*

That night in the Gryffindor boys' dorm, Snape draws the curtains around his four-poster with a sigh of relief. His Harry Potter impersonation seems to have passed muster so far. He's even discovered why Hermione isn't speaking to him: she disapproves of his apparently taking Ron's advice to hang back after Potions and get Slughorn alone (sensible girl). She also disapproves of Harry using the Half-Blood Prince's copy of _Advanced Potion-Making_ to gain an undeserved reputation for brilliance in Potions. (He's with her there, too.) He's gathered from Ron that Harry is even in the habit of poring over the book in bed at night. Much to his surprise, he finds this almost touching.

A dull buzzing in his ears tells him that someone nearby has cast _Muffliato_. So, Potter's shared the Half-Blood Prince's spells far and wide, has he? Hmm. It's probably Ron Weasley having a wank. He turns over restlessly, but sleep eludes him. Maybe he should follow Weasley's example. The thought of using Potter's privates to wank with is curiously titillating. Telling himself firmly that this is nothing like Slughorn's behaviour, he reaches for his wand...

*

  


The next morning, Snape saunters into the DADA classroom, smirking to himself. He's looking forward to embarrassing Potter. Maybe he'll treat him to some of the dumb insolence the brat usually displays towards _him_.

When he looks around him, he sees that Potter has already made some changes: the curtains are drawn back, letting in the cold February sunlight; the gruesome pictures are gone from the walls; a large tank full of Grindylows stands on a table near the teacher's desk. Snape bares his teeth. So we're taking Remus Lupin as a role model, are we?

The door bangs open and Snape watches sourly as his impersonator strides to the front of the class, black robes billowing. He's got _that_ right, at least.

"Settle down!"

The voice isn't quite right, Snape thinks critically, but he doubts any of these dunderheads will notice. Now let's see what sort of a cock-up Potter will make of things.

As the lesson proceeds, he's forced to admit that Potter isn't doing too badly at all. He still wants to cause him some embarrassment, however, and his chance comes when they're split into pairs to practice non-verbal jinxes and counter-jinxes. Having reduced Ron Weasley to incoherence with a Hysteria Hex, he slyly fires a Spinning Spell at his doppelganger over Weasley's shaking shoulders.

"Oops, missed," he says gleefully.

"Give me that wand, you little shit," snaps a pirouetting Potter. "I'm confiscating it."

Giving Potter full marks for getting his wand back, he reluctantly hands it over.

"And I'm giving you detention," adds Potter, performing the counter-jinx before stowing his wand away protectively inside his robes. "My office.Tonight. 8 o'clock."

*

  


Harry sits in Snape's office idly twirling his wand between his fingers. He's not taken a swig from his flask of Polyjuice potion since dinner in the Great Hall, and the last dose has just worn off. It's a relief to be himself for a bit.

A knock on the door sends his hand diving for the flask, then he relaxes: it's probably just Snape, come for his detention. He stands well back in the shadows, flask in hand, as he calls "Enter", only stepping forward when he's sure it's Snape.

Within seconds, it's turned into a slanging match.

"I told you to keep taking the potion every hour, anyone might walk in –"

"When the fuck are you going to get your _improved_ version fixed, potions genius? I don't _enjoy_ being a greasy git –"

"Oh, and you think I enjoy being a scrawny four-eyed brat –"

"What's with you and Filch, anyway? Ewww –"

"Stealing my fucking potions notes –"

Silence. They stare at each other with identical looks of shock on their identical faces.

At last, Harry says,"Wait, what? _Your_ potions notes?!"

And Snape replies, "Yes, _my_ potions notes. I am – I was – the Half-Blood Prince."

*

  


February gives way to March. Despite all his efforts, Snape hasn't yet found a way to reverse his Polyjuiced state. He and Potter have reached a fragile understanding: they have weekly meetings in the guise of detentions, when they exchange briefings on how to lead the other's life. This morning, for example, he's to give Weasley the birthday present which Potter has already acquired and wrapped for him.

"Happy birthday," he says, throwing the package onto Weasley's bed, before diving into Potter's trunk to dig out the Marauders Map, which he hides between uses in case any other occupant of the Gryffindor boys' dorm notices that the footprints labelled _Severus Snape_ are located right beside him.

"I solemnly swear I am up to no good," he mutters and taps the Map, thinking, as he always does, evil thoughts about its manufacturers. He scrutinises the Map to see what Potter's up to this morning – ah, there he is, at breakfast in the Great Hall already, sitting next to that oaf Hagrid. No problem there, then. Hagrid won't notice anything untoward about 'Professor Snape'. It's the increasingly rare occasions when Dumbledore is present which really worry him.

Relieved, he taps the Map again and murmurs "Mischief Managed."

Then he looks across at Weasley, surrounded by presents and torn wrapping paper, stuffing his face with chocolates.

"Coming to breakfast?"

The boy gawps back at him, a strangely unfocussed look on his face. "I'm not hungry."

Snape looks at him suspiciously. Weasley is showing all the signs of having taken some illicit potion or other. His suspicions are confirmed when the boy bursts out, "Harry, I can't stop thinking about her!"

Right. A love potion, then.

"Who?" he asks warily.

"Romilda Vane," Weasley breathes, his face lighting with besotted happiness.

Snape considers various possibilities before reluctantly deciding on the most Potteresque course of action.

"She'll be in Slughorn's office," he declares, leading the way to the door.

Slughorn answers his office door at the first knock, wearing a green velvet dressing gown and matching nightcap. "Harry," he yawns, "this is very early for a call... I generally sleep late on a Saturday..."

He can see Slughorn wondering if his luck's changed, hastily pushes Weasley in front of him, explains the situation.

"I'd have thought you could have whipped him up a remedy, Harry, an expert potioneer like you?" asks Slughorn.

 _Like hell he could,_ thinks Snape with a sneer; says aloud, "Er, well, I've never mixed an antidote for a love potion, sir, and by the time I get it right he might've done something serious –"

"Was this potion within date?" asks Slughorn. "They can strengthen, you know, the longer they're kept."

 _I know that, you old fool_. "It's his birthday, Professor," he says in sickeningly imploring tones, just how Potter would.

"Oh, all right, come in then," says Slughorn, "I've got the necessary here in my bag, it's not a difficult antidote."

And in fact he makes a reasonably good job of it, not as elegant a solution as Snape would prefer, but good enough for a Weasley. He even offers them a drink afterwards.

"Happy birthday, er, Ralph," Slughorn says, handing them glasses of mead before raising his own, "and may you have many more –"

But Weasley has dropped his glass after one sip, is slumped in his chair, is choking and jerking uncontrollably.

"Professor!" bellows Snape. "Do something!"

But Slughorn seems paralysed by shock. Fucking typical. The boy could die before he gets his fat finger out. Snape sprints towards Slughorn's open potion kit, fingers rapidly rifling through it till he finds what he needs. A moment later, he's back at Weasley's side, forcing his mouth open, thrusting the bezoar inside.

He's only just in time.

*

  


It's late that evening. Snape is continuing his Harry Potter impersonation beside Ron's bed in the hospital wing, surrounded by a crowd of Weasleys and others, desperately trying to think of an excuse to leave.

The last straw comes when Mrs Weasley flings her arms around him and hugs him to her saggy breasts.

"Dumbledore's told us how you saved him with the bezoar," she sobs. "Oh, Harry, what can we say? You saved Ginny... you saved Arthur... now you've saved Ron..."

"Don't be... I didn't..." he mutters, restraining himself – just – from hexing her.

He's saved by Madam Pomfrey, who tells them sternly there are only supposed to be six visitors per patient. He leaves thankfully, accompanied by Hermione Granger and Hagrid. As they walk along the corridor, he's thinking for the thousandth time that this can't go on, someone's sure to rumble either himself or Potter before long. And as he's thinking this, he realises what Hagrid has just said.

"... no wonder Dumbledore's angry with Sn–"

Hagrid stops, looking guilty.

"What? Dumbledore's angry with Snape?" Snape says quickly, thinking _oh fuck, what has that stupid boy done?_. "Why, Hagrid?"

"I dunno, Harry, I shouldn'ta heard it at all! I – well, I was comin' outta the Forest the other evenin' an' I overheard 'em talkin' – well, arguin'. Didn't like ter draw attention to meself, so I sorta skulked an' tried not ter listen, but it was a – well, a heated discussion, an' it wasn't easy ter block it out."

 _Oh, no._ "Well? Go on!" he says.

"Well – I jus' heard Snape sayin' Dumbledore took too much fer granted an' maybe he – Snape – didn' wan' ter do it any more –"

"Do what?" _What the fuck does that stupid brat think he's playing at?_

"I dunno, Harry, it sounded like Snape was feelin' a bit overworked, tha's all – anyway, Dumbledore told him flat out he'd agreed ter do it an' that was all there was to it. Pretty firm with him. An' then he said summat abou' Snape makin' investigations in his house, in Slytherin..."

Snape groans inwardly. This is all he needs.

As he finally gets free of Hagrid and Granger, there's only one thought in his mind. He has to get hold of Potter, NOW, and find out what the fuck's been going on.

*

  


Harry's pacing the corridor outside the Room of Requirement, determined to catch Draco Malfoy and find out what it is he does in there. He has to concentrate on this obsession to the exclusion of everything else. Otherwise, he'd have to think about the things Dumbledore has said to him, thinking him Snape, things he'd never say to Harry Potter. And he can't think about them. Not without going mad.

 _So, Malfoy. When are you coming? Or are you in there already? I can wait all night if I have to. I don't need to worry about curfews. As Snape, I can patrol any corridors I like, for as long as I like. And when I catch you, Malfoy, I'll –_

His thoughts break off. What's that noise, behind him? Is it Draco Malfoy, trying to sneak past? He whirls, seeing nothing but empty corridor, then gasps, startled, as an unseen hand grabs his arm. A voice growls in his ear.

"We need to talk, Potter. NOW."

And the corridor wall immediately melts away, the Room of Requirement responding to the raw urgency in Snape's voice as it's never responded to Harry in all his weeks of trying. Harry steps inside, looking eagerly for some sign of Malfoy, but the Room has evidently decided that he and Snape are here for a cosy tête-à-tête. It's much smaller than he remembers it from the days of Dumbledore's Army – just an intimate little room containing a couple of armchairs beside a glowing fireplace, a low table between them bearing bottles, two glasses and a heaped plate of snacks. The whole atmosphere is one of warmth, and comfort, and _safety_.

Harry sinks into one of the armchairs and lets out a long sigh. His whole body seems to echo the sigh, and he realises his latest dose of Polyjuice is wearing off. Automatically he reaches for his flask, then realises that, here, he doesn't need it; the Room allows him the luxury of being himself.

A luxury unfortunately denied to Snape, who lifts his Disillusionment Charm to reveal him sitting, a second Potter, in the other armchair. He blurs as Harry's transforming eyesight weakens. Harry rubs his eyes and groans.

"Here." Snape's pushing a pair of glasses into his hands.

"Thanks."

There's a long silence. They both stare into the flickering flames. Harry's almost asleep when Snape's voice snaps him back to wakefulness.

"What were you arguing about with Dumbledore?"

"Arguing?" he asks stupidly, to buy himself time.

"In the Forest, the other night. Hagrid heard you. He said you were having _a heated discussion_ and that you _didn't want to do it anymore_. What, Potter? What don't you want to do?"

Harry groans again. "He said that I – well, you – will kill him. _After you've killed me_ he said."

"So what did you say to him?" Snape asks urgently.

"I panicked, right?" Harry says, rubbing his fist across his face. "I said no way would I kill him. He said I'd agreed, that I must. I tried to get more information, without letting on that I wasn't really you, but he just started talking about Draco Malfoy." He slaps his hand down on his knee. "I _knew_ Malfoy was up to no good, I keep telling people, but nobody believes me –"

His voice breaks, his chest heaves. For a moment he's fighting to suppress it all, then something – the magic of the Room maybe – crumbles his resistance, and he finds himself sobbing, deep tearing sobs.

And Snape finds himself on his knees beside the boy's chair, his arms around him, offering what comfort he can.

*

  


Harry sits among the Quidditch spectators, wrapped in Snape's Slytherin-green match-going robes. Of all the indignities and dangers which their role-swap has engendered, this strikes him as one of the worst. Forget Filch's attentions, the need to avoid Dumbledore, the whole killing thing. What's worrying him most at this precise moment is that Gryffindor's prospects of beating Hufflepuff are considerably diminished by having Snape as their Seeker.

He knows he's infuriated Snape during their past couple of conferences – they meet nightly, now, in the Room of Requirement – by his inability to talk about anything other than Quidditch tactics. Well, that and Draco Malfoy. He's not sure which topic annoys Snape the most.

The match gets underway. He must remember not to cheer when Gryffindor score. The sight of his look-alike circling aimlessly above the pitch does nothing to improve his mood; can't Snape see the Snitch – it's over there, look! McLaggen is being a prat – as usual – and Harry's a mere onlooker, unable to do anything about it, and wearing Slytherin colours to boot. The situation is surreal, an impression which Luna Lovegood's match commentary does nothing to dispel.

Oh, shit. What's that idiot McLaggen doing now? He's taken the bat away from Peakes, one of the Gryffindor Beaters, and seems to be showing him how to hit a Bludger. Harry leans forward, just stops himself in time from shouting abuse. His counterpart on the pitch has noticed, too; he's given up his search for the Snitch and is speeding towards McLaggen, shouting _"Will you give him back his bat and get back to the goalposts!"_

McLaggen takes an almighty swipe at the Bludger. Harry stares, horrified, as it zooms straight for Snape. There's a sickening _crack!_ as Bludger meets skull, and Snape's off Harry's broom, he's falling, falling...

... he's on the grass, limbs asprawl, frighteningly still.

*

  


It's dead of night, everyone's asleep. Or so Harry hopes, as he slips quietly into the Hospital Wing. Moonlight shines through the uncurtained windows, throwing eerie shadows across the room. Ron's snoring loudly in his bed.

The next bed has curtains drawn round it. An icy clutch of dread squeezes his heart. Please don't let that mean...

Carefully parting the curtains, Harry lets out a sigh of relief as he sees the bandaged head turn restlessly on the pillow. He pulls up a chair, sits by the bedside. Snape's eyelids are twitching; he's dreaming. Wait. Not just the eyelids, his whole face is twitching, melting. As Harry watches, the nose grows longer, becomes beaky; the lips thin; black hair oozes out from under the turban-like bandage and flops onto the pillow. After all these weeks, Snape is himself again.

Harry looks down in silence at the man he used to hate, but, somehow, no longer does. Not just because he's been wearing Snape's face all this time; nor the reactions of the staff to Severus, as they call him; nor Dumbledore's unwitting revelations; not even that they're in this mess solely through Snape's desire to protect him from Slughorn, although all of these have played their part. It's mainly, he realises, the time they've spent together – first their fake detentions, then in the Room of Requirement. He realises, too, quite how devastated he would be if that Bludger had been fatal. Harry touches the thin hand lying outside the bedcovers.

In fact, he feels –

Snape's eyes snap open, fix Harry's with that once-dreaded black stare. "Well. How... flattering."

Harry goes red, but leaves his hand touching Snape's. "Sir. You've changed back."

Snape lifts his other hand, explores his face, winces as he touches the bandage. "So I have. Thank Merlin," he says. "I'm saved from any more Quidditch games."

Harry grins. "I'll make sure McLaggen's off the team by our next match." Then his face turns solemn. "He could've killed you."

"His failure must be such a disappointment to you," says Snape drily. His eyes bore into Harry's again. "Oh. I see I'm wrong." His voice holds a trace of wonder. He raises his arms clear of the bedclothes.

Obeying his instincts, Harry's on the bed in an instant, snuggling against Snape's chest.

"It wasn't an invitation, Potter," Snape says. "I'm not Horace Slughorn."

It takes Harry a few minutes to realise what he means. Then he says, "Damn right you're not. I wouldn't do this if you were." And he kisses Snape's mouth.

And then they're naked; their hands are sliding over each other's bodies, he's biting at Snape's neck, Snape's letting him. They're grunting with pleasure, with desire, before Snape thinks to cast Muffliato, but they're lucky, nobody hears.

The next spell Snape casts coats their hands with erotically-scented, sensation-enhancing lubricant; they stroke and squeeze and tug at one another until their cocks and balls are slippery and dripping with it and with sweat and, soon, with come.

As they lie together afterwards, Harry says, "Weird. I felt I... um... knew what your cock felt like, from... well... sort of wanking with it when I was Polyjuiced as you. But it's totally different when it's really you."

"Likewise," Snape murmurs, and Harry wonders whether that means Snape has wanked while in his, Harry's, form, and if so what it felt like. But he's tired, so tired, and before he knows it, he's asleep.

*

  


When Harry wakes, early the next morning, he's utterly confused about where he is, who he is. There's a memory of hot man-sex – with Snape of all people! – which makes him blush, but that was a just a wet dream. Wasn't it?

There's a rattle of curtain rings, and Madam Pomfrey's leaning over him.

"Ah, you're awake. Hmm, let's see now –" she runs her wand expertly around his head. "Good. _Very_ good." She sounds surprised. "You'd hardly know it had been broken."

Harry lifts his hand, feels the stiff cap of bandages. "What happened? I don't remember hurting my head –"

She tuts. "Broken skull, Mr Potter," she says briskly. "May have caused short-term memory loss. Nasty game, Quidditch. The number of injuries I get in here!" She turns away, whisks the curtains fully open, heads for her office. "Just rest a little longer," she calls back to him over her shoulder. "I should be able to discharge you today."

Harry leans back against the pillows, thinking hard. The past few weeks seem so surreal – himself as Snape? Snape as him? – maybe they haven't happened at all. Experimentally he touches the bandages around his head again. Could a blow on the head make him _imagine_ all this stuff? But he's sure he remembers being a spectator rather than a participant in the Quidditch match, seeing the Bludger hit someone who looked like him, but wasn't. And his head doesn't hurt... or does it?

Suddenly he scoops up his glasses from the bedside table, jams them on his nose. With a wary glance towards Madam Pomfrey's office, he swings his legs out of bed, leans towards the bedside locker, opens it. Inside is his schoolbag. Feverishly, he searches through it till he finds his copy of _Advanced Potion-Making_. He stares at the book for a long moment. Is Snape _really_ the Half-Blood Prince?

Finally he opens it, looking at the cramped handwriting in the margins. He's almost sure, now, that it's similar to the writing he's seen many times on a blackboard in the dungeons, laying out instructions for a complicated potion. Almost. Harry blows out a sigh of frustration.

"I'm not mad," he says aloud, leafing distractedly through the book.

Then he stops, and a grin spreads slowly across his face. There, on the last page, in black, fresh ink – blacker by far, fresher by years, than the faded scribbles in the rest of the book – is scrawled, in the Prince's handwriting, one more spell: _**Lubricatum**_.

And under it, the words: _**For Wanking.**_

 

-end-


End file.
